The number of different portable electronic devices is proliferating rapidly. Among the large number of portable devices that have been developed are cellular telephones, two-way radios, cordless telephones, handheld computers (e.g., personal digital assistants), and handheld audio players (e.g., MP3 players). In addition to the recent trend of combining the functionality of different portable electronic devices into a single device, manufacturers increasingly are incorporating additional functionality into portable electronic devices. For example, cameras recently have been incorporated into cellular telephones.
Many different data input schemes have been developed for portable electronic devices. For example, a cellular telephone typically includes an alphanumeric keypad in which a number and three or four letters are assigned to each key. To dial a number, a user simply depresses the key assigned to the desired number. To input a letter, on the other hand, a user must depress the key corresponding to the desired letter one or more times until the desired letter appears on the cellular telephone display screen. Some portable electronic devices include a touch screen display that displays an output and receive a touch input. Software may be used to display on the touch screen display icons, which may represent buttons or keys. A user may activate a desired function by touching the touch screen display region displaying the button corresponding to the desired function.